A student in an MA course in Linguistics was puzzled about the naming conventions of the discipline. He asked:
If morphology is the study of word-structure, why can’t it be called wordology?
There are two answers to that: the simplest one is that the term is derived from the Greek ‘morphe’ [form], and science has tended to derive names from the classical languages. So, the study of the human heart is cardiology, rather than *heartology, and so on. Using Latin and Greek to exchange scholarly information was something of a necessity in the past, as they were the only languages shared by early scholars. Although English has now subsumed the role of an academic lingua franca, naming conventions are slow to change (but change does indeed happen).
A second, more technical reason, is that the discipline concerns itself with the study of morphemes, rather than actual words. Morphemes are the smallest meaningful units in a language; and there may be more than one in a single word (e.g., ‘words’ is comprised of a morpheme meaning ‘word’ and another one indexing plural). Calling the discipline *wordology might conceal its main focus.
NB You may want to read further comments in this discussion thread.